Technical and regulatory due diligence of a Southern European gas transmission operator

Client: A leading European infrastructure fund (€5+ billion AUM) · Sector: Gas transmission · Mandate: Capital opening due diligence

Zelya Energy supported a European infrastructure fund on a technical and regulatory due diligence covering a Southern European gas transmission system operator (TSO), in the context of a capital opening transaction. The mandate accompanied the fund's entry alongside existing shareholders.

Gas TSOs concentrate regulatory complexity (third-party access rules, tariff methodology, unbundling) and capital-intensive infrastructure (high-pressure pipelines, compression, metering). Independent due diligence is essential to identify both regulatory exposure and operational risks affecting the regulated asset base trajectory.

What we did

• Analysed the regulatory framework: network access tariffs, allowed cost of capital, regulatory periods
• Reviewed the regulated asset base (RAB) evolution, depreciation profile and capex programme
• Assessed operational performance: balancing, congestion management, capacity allocation
• Verified compliance with unbundling requirements (legal, functional, certification)
• Built the independent valuation framework around regulated returns and downside scenarios

Result

Our regulatory review identified two areas of exposure linked to the upcoming tariff revision (third-party access fees, balancing services). Both were quantified and integrated into the financial model. The fund entered the capital opening transaction with full visibility on regulated revenue trajectory and stress scenarios.

This engagement is part of our gas sector due diligence practice, integrated within our cross-sector energy and renewable asset due diligence services.

Investing in regulated gas infrastructure? See our due diligence services on gas networks and energy infrastructure.